1. Field of the Invention
The present invention relates to a combined container-syringe that is filled with and contains a liquid medicine in advance and is capable of taking out from a packaging and immediately using the same when used.
Priority is claimed on Japanese Patent Application No. 2010-234873, filed Oct. 19, 2010, the content of which is incorporated herein by reference.
2. Description of Related Art
Since the combined container-syringe is filled with a liquid medicine in advance, the combined container-syringe can immediately be taken out from the packaging and used in a medical institution without a complicated operation. Since the combined container-syringe is extremely convenient and greatly contributes to the reduction of the work of those engaged in a medicine practice such as doctors or nurses, the combined container-syringe is adopted in many hospitals.
In the related art, as a kind of combined container-syringe, a dual chamber combined container-syringe is known in which a pharmaceutical preparation and a liquid medicine are separately filled.
The dual chamber combined container-syringe is configured such that a front stopper is fitted into a tip side of an outer casing, an end stopper is fitted into a rear end side thereof, and an inner portion of the outer casing is divided into two front and rear chambers by a middle stopper fitted into a central portion in the outer casing. Furthermore, in a portion of the tip side further forward than the middle stopper in the outer casing, a bypass portion is formed in which a part of an inner peripheral surface of the outer casing is formed so as to bulge outward. In addition, the front chamber of the tip side of the middle stopper is filled with powdered pharmaceutical preparation, and the tip thereof is sealed with the front stopper. Meanwhile, the rear chamber of the rear end side of the middle stopper is filled with the liquid medicine, and the rear end thereof is sealed with the end stopper. In addition, a plunger rod is connected to the rear end of the end stopper.
When using the dual chamber combined container-syringe having such a configuration, the end stopper is moved forward in the outer casing by pushing the plunger rod into the outer casing. Then, the pressing force due to the forward movement of the end stopper is transmitted to the middle stopper via the liquid medicine, whereby the middle stopper is moved forward along with the forward movement of the end stopper. Moreover, when the middle stopper reaches the bypass portion, the two front and rear chambers of the middle stopper communicate with each other via the bulged portion of the bypass portion. As a result, the liquid medicine of the rear chamber flows in the front chamber, and the liquid medicine and the pharmaceutical preparation of the front chamber are mixed with each other, whereby an injection drug is prepared.
Japanese Unexamined Patent Application, First Publication No. 2007-111156 is an example of the above-described related art.
In the dual chamber combined container-syringe mentioned above, in order that the liquid medicine and the pharmaceutical preparation can be suitably mixed with each other, until the entire liquid medicine of the rear chamber flows in the front chamber, the middle stopper needs to remain in the bypass portion. Furthermore, in the case of a pharmaceutical preparation that is not easily dissolved, there is a need to control the inflow of the liquid medicine.
However, when the plunger rod is pressed too fast, or when the plunger rod is too strongly pushed without confirming the ending of the inflow of the liquid medicine to the front chamber, the middle stopper is moved to the tip side further than the bypass portion in the state in which not all the liquid medicine can flow in the front chamber. As a result, a situation is generated where the liquid medicine in the rear chamber remains without being mixed with the pharmaceutical preparation.
In this manner, depending on an erroneous operation of the plunger rod, an unnecessary liquid medicine is generated which is never mixed with the pharmaceutical preparation. As a consequence, there is a problem in that the injection drug of a given concentration cannot be prepared, and the pharmaceutical preparation is not sufficiently dissolved by the liquid medicine.
The present invention was made in view of the problems, and an object thereof is to provide a dual chamber combined container-syringe that is capable of reliably and suitably mixing the liquid medicine with the pharmaceutical preparation according to the natures thereof.